I think items should have less of a fixed value in Fallout 3. It could be dictated by supply and demand, and of course the values could be different in each reason. For example, stimpacks would be more valuable in Redding than in Vault City, whereas gold is more valuable in Vault City than in Redding. Also, this would allow for trade goods to be used. Things that are of minimal use to the character, but are important in towns, like tools for making bricks or gate hinges. Sure, you could find uses for them, but primarily they could be used as a commodity to trade. You should never get enough of them to form your own caravan or something, but being able to dabble in trading like that to make some pocket cash would be a nice touch, in my opinion.